/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package org.apache.commons.exec.launcher;

import java.io.File;
import java.io.IOException;
import java.util.Map;

import org.apache.commons.exec.CommandLine;

/**
 * Interface to shield the caller from the various platform-dependent
 * implementations.
 */
public interface CommandLauncher {

	/**
	 * Launches the given command in a new process.
	 * 
	 * @param cmd
	 *            The command to execute
	 * @param env
	 *            The environment for the new process. If null, the environment
	 *            of the current process is used.
	 * 
	 * @return the newly created process
	 * @throws IOException
	 *             if attempting to run a command in a specific directory
	 */
	Process exec(final CommandLine cmd, final Map env) throws IOException;

	/**
	 * Launches the given command in a new process, in the given working
	 * directory.
	 * 
	 * @param cmd
	 *            The command to execute
	 * @param env
	 *            The environment for the new process. If null, the environment
	 *            of the current process is used.
	 * @param workingDir
	 *            The directory to start the command in. If null, the current
	 *            directory is used
	 * 
	 * @return the newly created process
	 * @throws IOException
	 *             if trying to change directory
	 */
	Process exec(final CommandLine cmd, final Map env, final File workingDir)
			throws IOException;

	/**
	 * Checks whether <code>exitValue</code> signals a failure on the current
	 * system (OS specific).
	 * <p>
	 * <b>Note</b> that this method relies on the conventions of the OS, it will
	 * return false results if the application you are running doesn't follow
	 * these conventions. One notable exception is the Java VM provided by HP
	 * for OpenVMS - it will return 0 if successful (like on any other
	 * platform), but this signals a failure on OpenVMS. So if you execute a new
	 * Java VM on OpenVMS, you cannot trust this method.
	 * </p>
	 * 
	 * @param exitValue
	 *            the exit value (return code) to be checked
	 * @return <code>true</code> if <code>exitValue</code> signals a failure
	 */
	boolean isFailure(final int exitValue);
}
